Consume own error chan to finish the heartbeat

Instead of a data race on closing or nil'ing the Connection.sends chan,
wait for completion from a buffered Connection.NotifyClose chan.
Isolate locks for channel registry

In response for finding a race that requires finer grained locking, use
a synchronized registry that manages the sequence and sequence to
channel map.

This removes the routability of a connection to channels during a
channel shutdown.  Assumes that no AMQP messages should arrive after a
connection shutdown arrives which may not be correct.
Update server cert to include subjectAltNames

Go1.1 has stricter client checks that must include an IP match when an
IP is used for the server name.

Add IP.1=127.0.0.1 under the subjectAltNames section of the openssl
config for the custom certificate authority and re-request a server
cert.